Wrenches have been around for hundreds of years and they generally have openings or orifices formed to control the rotation of a work piece such as a fastener, nut, bolt, etc. As long as there have been wrenches, there have been wrench engagement failures, whereas, a wrench slips or fails to properly grip a work piece under torque. Wrench engagement failures often result in damage to the work piece, damage to the wrench, and sometimes user injury. Over the past couple decades, lateral engagement designs have been greatly improved, providing “off corner” loading and “force distribution” to minimize lateral engagement failures. Nonetheless, the improved lateral engagement designs only affect improvements in lateral (horizontal) engagement, not longitudinal (vertical) engagement. In fact, applicant believes that the newer lateral engagement designs actually reduce longitudinal engagement contact, and in some instances, actually fail to engage with as much as 35% of the vertical surfaces of a work piece such as a fastener, nut, bolt etc. To make matters worse, the loss of engagement occurs at the base of the work piece, believed by applicant to be the most critical area of engagement necessary to reduce wrench engagement failures and maximize torque capacity.
In addition, wrench engagement failures often occur when a wrench becomes disoriented or tilted on a work piece under torque. These types of engagement failures are referred to herein as “tilt-off” events. More specifically, applicant defines a “tilt-off” event as an engagement failure that occurs when a user is turning a work piece such as a fastener (either tightening or loosening) and the wrench becomes slightly tilted on the fastener. When this occurs, the forces involved tend to push the wrench away from and off the fastener often damaging the fastener and/or wrench, and possibly injuring the user. Engagement failures also occur when a wrench is turning a fastener that is rusted, eroded or otherwise tapered from its base. Applicant defines a “taper-off” event as an engagement failure that occurs when a user is turning a work piece such as a fastener (either tightening or loosening) which is slightly rusted, eroded or otherwise tapered from its base. When this occurs, the forces involved tend to push the wrench away from and off the fastener often damaging the fastener and/or wrench, and possibly injuring the user. Applicant believes that the “tilt-off” and “taper-off” events defined herein occur easily and frequently because it is difficult for a user to maintain a continuous, properly seated relationship between a wrench and fastener when both are being forcibly turned, and, it's very common to encounter a fastener which is slightly rusted, eroded, or tapered from its base.
Therefore, applicant believes there is a significant need to improve upon prior art wrench opening designs to overcome the deficiencies identified above.